Honeywell NA 228 S-C Product specification sheet

NA 228 S-C

Automatic refilling unit for open heating systems

Product specification sheet

						4
	GRÄSSLIN				2		6
	h				0	bar	8
UWZ 52	220V~50Hz
vom
Kaltwassernetz						10
				5
SPX						15
1996					bar
				0
						16
		Typ:		NA 228			30 Watt
	/ DVGW				Hz
NachfüllautomatTÜV		~	50/60
	230V
Construction

The automatic refilling unit comprises:

●Powder coated pressed steel housing

●Drinking water and system connection with shutoff ball valve

●Counter with reset key

●Electronic time relay

●Fault indicator lamp and cut-out button

●Pressure gauges for inlet and system pressure

●Discharge tundish

●ON/OFF switch

●1.5 metre plug-in connection cable

●Water meter

●Bush for cable connection to a building management system

●Level control

●Electronic level probes

●Electronic level probes connection and 1 metre mass cable connection prepared

*For temperatures above 100 ºC, the pressure at the highest point in the cold system must be at least 1.0 bar above the operating pressure (static height plus 1.0 bar).

Subject to change

03/99

Application

The NA 228 S-C automatic refilling unit with DVGW-tested backflow preventer permits the fixed connection of open heating systems to the drinking water supply network.

It integrates a backflow preventer, a check valve and a water meter in one single unit. The automatic refilling unit maintains pressure between prescribed upper and lower limits in open heating systems. It prevents back flow, back syphonage or back pressure of the heating water into the potable water network. Limitation of the refilling time is provided as well as the facility for fast and automatic refilling of the system. In addition, build up of steam in the system caused by pressure loss is prevented.

Special Features

●Components DVGW-approved

●Electrical changeover valve for control of the backflow preventer

●Supplementary hot-water-resistant check valve for increased protection of the drinking water network

●Setting facility for fast filling or refilling of the system

●Time relay, for limitation of the refilling period

●Standardised discharge connection

●Remote volt-free connection for electronic level probes and mass cable

●Bush for cable connection to a building management system

●Circuit protection for volt-free connection

●Water meter, measures the refills

●Electronic level probes for level monitoring

Range of Application

The following operating data applies for the downstream system:

System pressure	Maximum 4.0 bar
Temperature	Maximum 120 ºC
Technical Data
Refilling	Flow rate 110 litres/h at p = 2.0 bar
Fast filling	Flow rate finely adjustable between
	110 litres/h and 1100 litres/h at p=2.0 bar
Filling duration	Adjustable between 5 and 100 minutes
Water level	Upper and lower level indicated by
	electronic level probes
Probes distance	approx. 200 mm
Water inlet pressure	Minimum 1.5 bar, maximum 4.0 bar
Remote connection	220 V, 50/60 Hz to activate compressor
	level indicator switch „lack of water“
	Volt-free contact
Supply voltage:	230V, 50/60 Hz
Power consumption:	30W
Connection size:	R 1/2" and Ø15
	229

Automatic Refilling unit NA 228-SC

T	B
NETZ
EIN/AUS
Fremdanschluß
- potentialfrei -
			H
zur Heizungsanlage
0 0 0 0 0 0 0 0	5		10
	0	bar	15
			16

Connection size	R	1/2"
Soldered connection size (mm)		Ø15
Weight	(approx kg)	16
Dimensions	(mm)
H		380
B		370
T		160
Test Certificate Number		101/87/147

Method of Operation

If the system pressure falls below the lower set value, for example through leakage losses, then the changeover valve is opened by electronic level probes control and thereby permits water supply to the backflow preventer. The inlet pressure moves the backflow preventer to the flow position and the system is refilled until the pressure rises to the upper set limit. The time period of the refill is monitored by the time relay. Once the upper limit value has been reached, the level control closes the changeover valve and the backflow preventer goes to the shutoff position. The time relay then returns to the initial position.

If the inlet pressure falls to the set pressure of the backflow preventer during the automatic refilling operation, then the backflow preventer (1 bar) automatically goes to the shutoff position. The shutoff position of the backflow preventer is indicated in the viewing window (green visible = shutoff position)

Option

NA 228 S-C

230

Braukmann Water Control . Honeywell AG

Subject to change

03/99